A fan with a diameter of 10cm is spinning at 25 revolutions per minute clockwise. The fan's reference blade starts pointing directly upwards. Determine an equation for a sinusoidal function that represents the fan's reference blade's vertical distance from the center (a negative value being accepted). State the period, amplitude and vertical shift for this function.

2 answers

I need help please. I have to finish this question.
since the curve starts at the top when t=0,

y = a cos(kt)

the diameter is 10, so the radius is 5:

y = 5 cos(kt)

The period is 1/25 min, so 2pi/k = 1/25, making k = 2pi/25

y = 5 cos(2pi/25 t)

Not sure what you mean by the blade's distance from the center. I think you meant the tip of the blade.